Bone cement is used during many orthopaedic arthroplasty procedures in order to securely attach the arthroplasty implant to the patient's bone. It is of vital importance to ensure that sufficient cement is applied to ensure good interlock. The amount of interlock depends on a number of factors such as pressurisation, bone density and any cavities present. These factors currently require the surgeon to apply more cement than is actually required. If too little cement is used, then the implant may fail by becoming partially or wholly detached from the bone. This may require revision surgery, if there is sufficient remaining bone stock, or some other remedial procedure.
It can also be important to ensure that the bone cement is used when it is at the correct consistency as it cures. If the cement is used too soon during its cure, then the cement can be too runny and may leak off the bone. If the cement is used too late during its cure, then its adhesive properties in securing the implant to the bone may be impaired and an insufficiently strong fixation may occur. Hence, there is also a window of time during which cement should be used. However, there is great demand for orthopaedic surgery procedures and surgeons do not have time to wait during the procedure to ensure that the cement is at the perfect point in its cure either in terms of its ease of handling or its adhesive properties for application to the bone.
If too much cement is placed on the bone then when the implant is placed, the implant often squeezes cement away from the bone at the edges and the cement tends to become trapped in and around the patient's joint. Similarly if the cement is too runny, the cement can run off the bone and accumulate in and around the patient's joint. Hence, the surgeon often has to spend considerable time and skill trying to clean excess cement from on and around the implant and joint using curettes, scalpels or by hand. Otherwise, the cement, when dried, will harm the patient and may require surgical intervention to remove. It can be particularly difficult to ensure that all cement is removed as often there is very limited access to the joint. For example if may be necessary to try and remove cement from behind a knee joint and access to that space may be very limited. This is particularly the case during minimally invasive surgical procedures. Therefore, both the risk of leaving cement pieces in the joint and also scratching the implant surface is high.
Hence, apparatus and methods for improving the handling of bone cement during placement of an orthopaedic implant would be beneficial.